title: A longitudinal study of hospitalization rates for patients with chronic disease: results from the Medical Outcomes Study.
abstract: OBJECTIVE
  To prospectively compare inpatient and outpatient utilization rates between prepaid (PPD) and fee-for-service (FFS) insurance coverage for patients with chronic disease.
  
  
  METHODS
  Data from the Medical Outcomes Study, a longitudinal observational study of chronic disease patients conducted in Boston, Chicago, and Los Angeles.
  
  
  METHODS
  A four-year prospective study of resource utilization among 1,681 patients under treatment for hypertension, diabetes, myocardial infarction, or congestive heart failure in the practices of 367 clinicians.
  
  
  METHODS
  Insurance payment system (PPD or FFS), hospitalizations, and office visits were obtained from patient reports. Disease and severity indicators, sociodemographics, and self-reported functional status were used to adjust for patient mix and to compute expected utilization rates.
  
  
  RESULTS
  Compared to FFS, PPD patients had 31 percent fewer observed hospitalizations before adjustment for patient differences (p = .005) and 15 percent fewer hospitalizations than expected after adjustment (p = .078). The observed rate of FFS hospitalizations exceeded the expected rate by 9 percent. These results are not explained by system differences in patient mix or trends in hospital use over four years. Half of the PPD/FFS difference in hospitalization rate is due to intrinsic characteristics of the payment system itself.
  
  
  CONCLUSIONS
  PPD patients with chronic medical conditions followed prospectively over four years, after extensive patient-mix adjustment, had 15 percent fewer hospitalizations than their FFS counterparts owing to differences intrinsic to the insurance reimbursement system.
authors.affiliation: Community and Family Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA.
authors.forename: E C
authors.initials: EC
authors.lastname: Nelson
authors.forename: C A
authors.initials: CA
authors.lastname: McHorney
authors.forename: W G
authors.initials: WG
authors.lastname: Manning
authors.forename: W H
authors.initials: WH
authors.lastname: Rogers
authors.forename: M
authors.initials: M
authors.lastname: Zubkoff
authors.forename: S
authors.initials: S
authors.lastname: Greenfield
authors.forename: J E
authors.initials: JE
authors.lastname: Ware
authors.forename: A R
authors.initials: AR
authors.lastname: Tarlov
mesh_terms: D000328:Adult; D000368:Aged; D001900:Boston / Q000453:epidemiology; D002641:Chicago / Q000453:epidemiology; D002908:Chronic Disease / Q000191:economics* / Q000453:epidemiology; D018588:Fee-for-Service Plans / Q000706:statistics & numerical data*; D005260:Female; D006295:Health Resources / Q000706:statistics & numerical data; D006302:Health Services Research; D006760:Hospitalization / Q000191:economics / Q000706:statistics & numerical data*; D006801:Humans; D008137:Longitudinal Studies; D015141:Los Angeles / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017061:Prepaid Health Plans / Q000706:statistics & numerical data*; D011446:Prospective Studies; D012959:Socioeconomic Factors